This invention relates generally to machining, and more specifically to precisely holding a workpiece for wire electrical discharge machining. 
It is often a requirement to hold a workpiece in a specific position for a machining operation, then rotatably index it about an axis to a different angular position for another operation. Additionally, for subsequent operations, it may be a requirement to change the axis of rotation to a different angle relative to the machine base than on the first operation. 
It is also beneficial to have the lowermost part of the workpiece in close proximity to the lower wire guide of the machine. Prior art does not facilitate a change in elevation of the workpiece. 
In prior art these things are not easily accomplished and the machinist must often create special tooling to obtain the desired effect.  
Since wire electrical discharge machining is often done submerged in water, it is also necessary to have the workholding tool unaffected by the water, therefore prior art would seal the internal mechanisms to prevent contamination. 